Unlike other third-person action games, "InFamous 2" comes packed with its own mission editor, allowing you to design your own missions in the game and share them with others.
The editor comes with a variety of predetermined mission types including Search and Destroy, Survival, and Escort, et al, because everyone loves escorting dumb NPCs around.
Either way, the mission editor stands to prolong the replay factor of "inFamous 2" by quite a bit.